1. Field of the Invention
The present disclosure relates generally to a temperature control device and more particularly, to a heating device and a biochemical reactor having the heating device.
2. Description of the Related Art
Many biochemical reactors are equipped with heating devices such that biochemical reactions can be carried out in vessels at a particular temperature. A conventional heating device is mainly composed of a substrate, two conductive layers, and a heating element. The substrate includes at least one through hole for insertion of a vessel and at least one receiving hole located adjacent to the through hole for accommodating the heating element. The two conductive layers are formed on a part of the substrate and disconnected to each other. Upper and lower terminals of the heating element are respectively connected electrically to the two conductive layers by respective tin soldering. In use, the heating element can convert the electrical energy into heat energy to heat the vessel.
Because the tin soldering connecting the heating element and the two conductive layers may crack easily due to the stress caused by repeated expansions and contractions, the lifetime of the heating device may be shortened. In addition, during the welding process, a part of molten tin soldering may penetrate into a space between the heating element and a wall of the receiving hole by capillary action or force of gravity, or may be sucked into the space by vacuum suction due to the grounds that a vacuum suction force may be generated inside the space, which becomes a closed space when the welding at an terminal of the heating element is completed and the tin soldering at the other terminal of the heating element stays at a partially molten stage, when the substrate cools down to cause volume reduction of the closed space due to temperature decrease of the air inside the closed space. In this case, the tin soldering at one end of the heating element and the tin soldering at the other end of the heating element are connected to each other in the space. A short-circuit may occur therebetween, thereby lowering the production yield.